As part of the Department of Homeland Security, there is a requirement for emergency notification to air traffic controllers if an attack on a commercial aircraft is detected. For this purpose, commercial airliners are provided with a sophisticated aircraft defense system which is capable of reliably detecting a missile threat. This aircraft defense system typically utilizes a missile warning system called the Common Missile Warning System (CMWS) developed for the military. The CMWS is a highly classified system and care must be taken not to divulge classified information when reporting missile threats to the ground.
Note that the missile warning system typically operates in the ultraviolet and senses the excited emissions from a rocket motor exhaust. The system employs sensors and a central processor that provides a UV warner to sense the missile as it approaches. UV radiation is used because there is not a great deal of background clutter in the UV to confuse the warners. Moreover, rocket motors have a very high UV content.
The missile warning system utilizes a central processor running a classified counter-measure effectiveness algorithm. This algorithm is used to reach a conclusion that a given high level of confidence applies to a potential threat, meaning that a missile is in fact detected, as opposed to a cigarette lighter or street lamp with a broken dome on it. The detection and classification of a threat involves highly classified techniques which identify the threat, its location, and whether or not there are multiple targets involved.
Upon reaching a conclusion that a threat exists, a pointer tracker is directed to look at the detected object and to countermeasure the target using a jam head controller powered up with highly classified jam code information. This jam code information is transferred from the Electronics Control Unit, ECU, into a Jam Head Control Unit, JHCU, which in turn is coupled to a laser which has its output transmitted through the pointer tracker. All of the information used in detecting and counter-measuring a missile threat is part of the highly classified Operational Flight Program carried in an Electronics Control Unit, ECU. The ECU holds all of the classified OFP parameters in a User Data Module, or UDM.
More particularly, there is a Department of Homeland Security requirement to automatically and rapidly notify air traffic control that there is in fact a missile threat attacking a specific airliner. There is also a requirement to transmit not only just the fact of a warning but any information about where the aircraft is, where the threat might be, and to do so with an indication that is unambiguous in a secure fashion. The indication of a threat to a commercial airliner must be done automatically with no delays, noting of course that any delay is critical.
If there is in fact a real threat, one wants to alert the air traffic control system, and does not want a man in the loop, namely an individual, who is interpreting any results. More particularly, one does not want to rely on somebody looking out of the cockpit window to ascertain whether the threat is real or not. Thus, the alerting of the personnel on the ground is to be automatic to identify the aircraft, the location of the aircraft and the type of threat, if in fact there is a credible threat. At the very minimum, the system is to indicate that an incident has occurred against an aircraft at a particular location. Moreover, the system itself must be designed for an extremely low false alarm rate, one in literally millions of hours.
It will be appreciated that while there are many requirements for such a system, the primary requirement is to be able to detect and report a threat has been encountered, or that a threat has been defeated, and to make ground personnel, air traffic control or other agencies aware that something has occurred with a high degree of confidence.